Anorexia Nervosa and Bulimia Nervosa are disorders of eating behavior. Little is known about the psychological-biological phenomena of hunger, satiety, taste and eating behavior in these disorders. This information is crucial for evaluating and developing effective treatment interventions for Anorexia Nervosa and Bulimia Nervosa. The aim of the current proposal is to study hunger, satiety and taste reponses in controlled experimental paradigms and evaluate the relationship of these appetitive features to serotonergic function which is known to affect satiety. Twenty or more females from each of the following six groups will be studied: Anorexia Nervosa patients with and without Bulimia, normal weight Bulimia Nervosa patients with and without a previous history of Anorexia Nervosa, normal controls, and obese controls who do not binge or diet. There will be 3 testing conditions. 1. Hunger and satiety will be characterized quantitatively and qualitatively in a test meal paradigm. 2. Taste perceptions and preferences to sucrose and fat-containing stimuli will be measured. 3. Serotonergic function will be assessed by a. prolactin and cortisol response to the fenfluramine challenge test and b. number of "serotonin-2" platelet receptors and the physiological responsiveness of those receptors. Eating disorder patients will be tested before, shortly after and one year following treatment to determine stability of responses. First degree relatives of Eating Disorder patients will be compared to those of normal controls in hunger-satiety and taste responses to determine the presence of a familial component to these appetitive features.